1. Field of the Invention
This invention relates to a color fluorescent display device, and more particularly to a color fluorescent display device particularly suitable for use in color graphic display.
2. Description of the Prior Art
In general, color image display has been carried out by using a cathode ray tube (CRT). Unfortunately, the CRT fails to provide a miniaturized, lightweight and thin display device, because it is large-sized in itself. In order to obviate such a problem, it is highly desirable to develop a color fluorescent display device.
A color fluorescent display device which has been conventionally proposed is generally constructed in such a manner as shown in FIGS. 1 or 2. More particularly, a color fluorescent display device shown in FIG. 1 comprises a plurality of control electrodes g.sub.1, g.sub.2 --arranged in parallel in the column direction, anode conductors a.sub.1, a.sub.2, a.sub.3,--arranged along each of the control electrodes and opposite thereto, wiring conductors each connecting the anode conductors a.sub.1, a.sub.1,--in the same row together, and phosphors of red, green and blue luminous colors R, G and B respectively deposited on the anode conductors a.sub.1, a.sub.2, a.sub.3,--in the same column in regular order and in a repeated manner.
The other conventional color fluorescent display device shown in FIG. 2 comprises a plurality of control electrodes g.sub.1, g.sub.2,--arranged in parallel in the row direction, anode conductors a.sub.1, a.sub.2, a.sub.3,--arranged along each of the control electrodes g.sub.1, g.sub.2,--and opposite thereto, wiring conductors C each connecting the anode conductors a.sub.1, a.sub.1,--in the same column together, and phosphors of red, green and blue luminous colors R, G and B respectively deposited on the anode conductors in the same row in regular order and in a repeated manner.
However, the conventional color fluorescent display devices each have the following disadvantages.
The mesh-like control electrodes g.sub.1, g.sub.2 each are supported at the four sides thereof by a rectangular frame (not shown), a gap is defined between the adjacent frames so as to electrically isolate the frames from each other, and the adjacent control electrodes g.sub.n, g.sub.n+1 are arranged side by side at a fixed interval. Accordingly, the control electrodes g.sub.1, g.sub.2,--must be substantially reduced in width l, because the size of the fluorescent display device is limited. This not only fails in the high densification of display but also substantially reduces an area of each of the control electrodes g.sub.1, g.sub.2,--effective to control electrons to cause the decrease in the number of electrons impinging on the phosphors, to thereby fail to improve luminance of the display.
The phosphors of red, green and blue luminous colors R, G and B are deposited on the anode conductors a.sub.1, a.sub.2,--in a linear manner. Accordingly, luminous display by the combinations RG, GB and RB of the phosphors obtained by selecting any two of the phosphors in one picture cell or the combination RGB causes the luminous interval to be varied to adversely affect the tone of display. This requires a correction of the tone, the correction having been conventionally carried out by varying voltage to be applied to the phosphors R, G and B to vary the luminance of each of the phosphors.